Summary: DNS Performance
Impact of misconfigurations
During the past twenty years the Domain Name System (DNS) has sustained phenomenal
growth while maintaining satisfactory performance. However, the original design focused mainly
on system robustness against physical failures, and neglected the impact of operational errors
such as misconfigurations. Our recent measurement effort revealed three specific types of
misconfigurations in DNS today: lame delegation, diminished server redundancy, and cyclic
zone dependency. Zones with configuration errors suffer from reduced availability and
increased query delays up to an order of magnitude. Furthermore, while the original DNS
design assumed that redundant DNS servers fail independently, our measurements show that
operational choices made at individual zones can severely affect the availability of other zones.
We found that, left unchecked, DNS configuration errors are widespread, with lame delegation
affecting 15% of the DNS zones, diminished server redundancy being even more prevalent, and
cyclic dependency appearing in 2% of the zones. We also noted that the degrees of
misconfiguration vary from zone to zone, with most popular zones having the lowest percentage
of errors. Our results indicate that DNS, as well as any other truly robust large-scale system,
must include systematic checking mechanisms to cope with operational errors.
DNS vs. DHT-based naming systems
The current Domain Name System (DNS) follows a hierarchical tree structure. Several recent
efforts proposed to re-implement DNS as a peer-to-peer network with a flat structure that uses